Feed-Through Terminal Blocks for DIN Rail – Ratings & Selection

Loose wire connections inside control cabinets are a primary cause of equipment overheating and unplanned downtime. Replacing permanent splices with properly selected feed-through terminal blocks isolates single-point faults in seconds, cutting troubleshooting time from hours to minutes.

The JHD1-1.5 model demonstrates this principle: rated at 500 V with 17.5 A nominal current and a 3.5 mm width, it carries substantial load while maintaining a compact DIN rail footprint. When selecting a terminal, have you calculated the thermal derating under continuous load?

Electrical Performance and Temperature Rise Characteristics

Contact resistance directly determines the temperature rise at each connection point. Push-in connection technology applies constant contact force, counteracting the cold flow effect of conductors over time. Low and stable contact resistance keeps self-heating within safe limits, preventing insulation degradation and reducing fire risk.

For railway rolling stock and process control applications, these terminals must withstand ambient temperatures from -40°C to +105°C and vibration frequencies from 5 to 500 Hz. A feed through modular terminal block offers modular stacking that distributes mechanical stress across multiple connection points, maintaining signal integrity under continuous vibration.

Selection Logic Based on Application Scenarios

Control cabinets and PLC systems with high I/O density: When a cabinet exceeds 200 I/O points, single-level terminals occupy excessive rail length. And multi level terminal blocks stack signal, supply, and return circuits vertically—signal on the lower tier, power on the middle, and ground on the upper—reducing rail occupancy to one-third of single-level configurations. Is your current panel layout maximizing vertical rail space effectively?

Power distribution and commoning multiple circuits: Distributing one main supply to multiple field actuators often requires external jumpers, which introduce additional failure points. Multi conductor terminal blocks route three or four conductors through a single current bar, eliminating daisy-chaining and reducing voltage drop across long wire runs.

Installation Specifications and Four Critical Errors

Proper installation begins with rail selection. The JHD1-1.5 mounts on NS 35/7.5 or NS 35/15 DIN rails per EN 60715. The specified stripping length is 10 mm.

• Stripping length tolerance: Exposing less than 10 mm prevents the conductor from reaching the current bar clamping zone. Exposing more creates a phase-to-phase short-circuit hazard.

• Flexible conductor preparation: Fine-stranded wires require ferrules. A crimping factor deviation exceeding 0.8 increases voltage drop and promotes localized heating.

• Dissimilar metal mixing: Never mix copper and aluminum conductors in the same terminal unless the current bar has a special transition coating. Galvanic corrosion increases contact resistance over time.

• Plug-in bridge insertion sequence: Install bridging components (FBS 2-3.5 through FBS 10-3.5) from left to right with power disconnected. Inserting out of sequence deforms the bridge spring, compromising contact pressure.

Technical Parameters at a Glance

The current-carrying capacity below is measured at 40°C ambient. If the cabinet internal temperature exceeds this baseline, apply a derating factor.

Maintenance and Systematic Inspection

Marker strips (ZB3.5) allow circuit identification directly on each feed through terminals. Numbered terminals reduce fault-finding time by up to 70% during emergency repairs.

Infrared thermal imaging during annual preventive maintenance reveals developing issues before they cause failures. If two adjacent feed through terminal blocks show a temperature difference exceeding 15°C, the connection likely has oxidation or a loose clamping mechanism.

For accessory selection and mounting torque specifications, refer to the related installation guides.

Conclusion

Feed-through terminal blocks function as conductor bridges, but their reliability depends on three factors: current margin, vibration resistance, and installation craftsmanship. When facing high-density wiring requirements, do you prioritize rail space with standard single-level terminals, or avoid cabinet expansion costs through vertical stacking? Choose wisely—and always account for maintenance downtime across the entire equipment lifecycle.

Wiring Diagram
Thickness / Width / Height (mm)		3.5×30.8×45.4
Technical Parameters
Rated Data	Voltage (V)	500
	Current (A)	17.5
	Cross-section (mm²)	1.5
Crimping Range	Rigid Wire (mm²)	0.14-1.5
	Flexible Wire (mm²)	0.14-1.5
Insulating Material		PA
Flame retardant rating UL-94		V0
Stripping Length (mm)		10
Install the Guide Rails		TH35-7.5/TH35-15
		model
Partition plate		1.5G
Plug-in Bridge	2P	FBS 2-3.5
	3P	FBS 3-3.5
	4P	FBS 4-3.5
	5P	FBS 5-3.5
	10P	FBS 10-3.5
Marker Strip	blank	ZB3.5
	Horizontal Printing	ZB3.5
	Vertical Printing	ZB3.5
Dimensions